Iron bars, planks of wood, metal jugs and a garden chair have been discovered underneath the Gorrell Tank car park during repair work.
Engineers have removed more than 750 tons of silt from underneath the town's biggest car park following its closure in April.
Several concrete columns have also been repaired temporarily.
Southern Water say they were forced to close the pay and display for safety reasons after a number of pillars were found corroding in an inspection.
A fleet of tankers are stationed in the car park taking silt to a landfill site in Norwich while unusual items were discovered underneath.
They include a garden chair, iron bars, planks of wood and even tankards and metal jugs.
Southern Water say they hope to reopen half the car park by the end of July weather and tides permitting.
Project manager Jon Yates said: "Our repairs are now well under way and progressing as planned.
"All being well with the weather and tides, we should have half of the car park reopened by the end of July."
For more information visit www.southernwater.co.uk/gorrelltank.